Polisher and polishing method

ABSTRACT

A polisher for polishing a curved surface such as a concave surface of a spectacle lens has a structure in which a polishing pad  3  comprising water passing grooves  5  having a width W of 0.1 to 5 mm is adhered to a dome-shaped elastic base member  2 . The polishing pad  3  is composed of a plurality of pads  31 , and the water passing grooves  5  are formed at the gaps between the pads  31 , whereby the width W of the water passing grooves  5  are made small. It is effective to make the pads  31  polygonal in shape. The polishing pad  3  covers the moving region  6  of the work  8  to be polished. The polishing pad  3  is adhered through a high-tack adhesive layer  4 . A polishing method is adopted in which such a polisher  1  is used and the work  8  is polished by pressing the polishing pad  3  against the work  8 , whereby the polishing pad  3  adhered to the elastic base member  2  can be prevented from being stripped by an end edge of the work  8 , and generation of defective polish can be prevented.

This is a National stage entry under 35 U.S.C. § 371 of PCT ApplicationNo. PCT/JP02/00002 filed Jan. 4, 2002; the above noted application ishereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a polisher and a polishing method, andparticularly to a polisher and a polishing method suitable for smoothingor mirror finishing a curved surface of a lens or the like.

BACKGROUND ART

Conventionally, a method of producing a plastic spectacle lens has beenconducted by polishing an unpolished spectacle lens which is generallycalled a semi-finished lens and has a thickness greater than a finishedsize, as described in Japanese Patent Laid-open No. sho 47-14776. Thesemi-finished lens is fixed to a holding means for polishing by use of alow melting point alloy generally called “alloy”, the surface on theeyeball side (concave surface side) of the semi-finished lens fixed tothe holding means is roughly ground in a spherical surface or a toricsurface shape according to the prescription for the wearer, and is thensubjected to sanding, which is similar to lapping, and to mirror surfacepolishing, whereby the optical surface of the lens is finished inprecision.

In the sanding and polishing, a hard polishing dish made of aluminum, ahard plastic, foamed polyurethane or the like and having a curvedsurface shape is used. In addition, according to the purpose ofprocessing, a polishing pad of a different kind is adhered to thesurface of the hard polishing dish, and sanding and polishing areconducted. In concrete, the purpose of the sanding is to smoothen theroughly ground surface to a certain degree of surface roughness, and togrind off shape errors generated upon rough grinding so as to conform tothe shape of the hard polishing dish. The sanding is conducted by amethod in which a polishing pad for sanding called “fining pad” andholding on the surface thereof abrasive grains of silicon dioxide,aluminum oxide, silicon carbide or the like about 10 to 20 μm in graindiameter is adhered to the surface of the polishing dish, and sanding isconducted while pouring water. Though depending on the roughly groundcondition, the sanding is generally conducted in two or more stagesuntil a surface roughness in terms of Rmax of equal to or less than 10μm is finally obtained.

The purpose of the subsequent mirror surface polishing is to furthersmoothen the sanded surface and to finish to a desired optical surface.The polishing is conducted by a method in which a polishing pad forpolishing formed of nonwoven fabric is adhered to the surface of thepolishing dish used in the sanding or a polishing dish of the same shapeas the polishing dish used in the sanding, and polishing is conductedwhile supplying a slurry including abrasive grains dispersed in adielectric liquid.

FIG. 5 shows a mirror surface polishing method using a polishing dish.FIG. 5(a) is a general side view showing the condition where a concavesurface of a lens is polishing by use of the polishing dish, and FIG.5(b) is a top plan view of the polishing dish. As shown in FIG. 5(b), apetal-shaped polishing pad 100 having a petal shape is adhered to thesurface of a dome-shaped polishing dish 110 by utilizing an adhesiveprovided on the back side of the polishing pad 100. Most of polishingpads 100 commercially available for polishing a plastic spectacle lenseach have a petal shape comprising a circular pad provided with radialnotches 101 so as to conform to the curved surface shape of thedome-shaped polishing dish 110. As shown in a sectional view of FIG. 6,the commercially available polishing pad 100 has a structure in which alow-tack adhesive layer 105 is provided on one side of a nonwoven fabric103, with a primer layer 104 therebetween. The polishing pad 100 isadhered to the polishing dish 110 by utilizing the low-tack adhesivelayer 105. The polishing pad 100 covers substantially the surface of thepolishing dish 110. As shown in FIG. 5(a), polishing is conducted byfixing the convex surface of a lens 8 as a work to a work fittingportion 10 through a joining member 9 such as a low melting point alloy,pressing the polishing dish 110 against the concave surface of the lens8, rotating the polishing dish 110, and rotating and oscillating thelens 8 through the work fitting portion 10.

In recent years, however, high value added lenses in which the surfaceon the eyeball side of a spectacle lens is provided with an axiallysymmetric non-spherical surface, a non-spherical astigmatism surface, aprogressive surface, a composed surface of a toric surface and aprogressive surface, or the like have come to be produced. In the casesof these so-called free curved surface shapes, it is impossible tocontinuously rub the entire surface of the lens by use of a solidpolishing dish having a convex surface in the same shape as the concavesurface of the lens.

Therefore, the polishing dish 110 shown in FIG. 5 is changed to anelastic base member having a curved surface shape, the polishing pad 100with the petal shape shown in FIG. 5 is adhered to the elastic basemember to form an elastic polisher, the elastic polisher and the lensare rubbed against each other while pressing the elastic polisheragainst the concave surface of the lens, and the above-mentioned slurryis intermediately provided, whereby mirror surface finishing isperformed. Since the elastic base member can be rubbed against the lenswhile deforming following up to the concave surface shape, it ispossible to polish a free curved surface. As an example of the method ofpolishing following up to the work shape in this manner, there may bementioned the method disclosed in Japanese Patent Laid-open No. Hei8-206952.

In the case of using such an elastic polisher, the size of the elasticbase member 2 is much larger than that of the polishing pad 100 which isroughly equal to the lens 8 in diameter, as shown in FIG. 7. The reasonis that, since the polishing speed of the elastic polisher is lower thanthat of the hard polishing dish, it is necessary to enhance thecircumferential speed so as to enhance the polishing speed. Therefore,the outside diameter of the polishing pad 100 is much smaller than thatof the elastic base member 2, and, in order to cover the moving region 6of the work 8, the polishing pad 100 is adhered in the state of beingeccentric with respect to the center of the elastic base member 2, asshown in FIG. 7.

However, a polishing method using an elastic polisher obtained byadhering a conventionally commercialized polishing pad 100 for polishinga plastic spectacle lens to the surface of the elastic base member 2 hasthe following problems:

The polishing pad 100 is generally of the so-called disposable type suchthat the polishing pad 100 is replaced with a new one each time one workis processed. In addition, since the polishing pad 100 is presumed to beused by being adhered to the hard polishing dish, the adhesive force isset to be low taking into account the workability at the time ofstripping. Namely, it suffices for the adhesive force to endure at leastone polishing step. Therefore, where this type of polishing pad 100 isadhered to the elastic base member 2, the lowness of the adhesive forceleads to the following problems.

First, as shown in FIG. 7, at the time of polishing by relativemovements of the lens 8 and the elastic base member 2 while pressing theelastic base member 2 against the lens 8 at a predetermined polishingpressure, the elastic base member 2 is deformed by being pushed by thecircumferential edge of the lens 8, so that the sharp circumferentialedge of the lens 8 may easily get under the notch portion 101 or endedges of the polishing pad 100 having the petal shape. Therefore, thecircumferential edge of the lens 8 will easily get between the polishingpad 100 and the elastic base member 2, to strip the polishing pad 100.Besides, since the adhesive force is low, the polishing pad 100 cannotfollow up to the deformation in shape of the elastic base member 2,whereby the polishing pad 100 is stripped in many cases.

When even a part of the polishing pad 100 is stripped, the polishing padin the stripped part is folded, resulting in that the polished surfaceof the optical component part is scratched, a desired appearance qualitycannot be obtained in most cases, and defective polish is generated.Therefore, it is difficult to polish stably under the condition wheredurability to polishing is thus low.

Further, in order to regenerate the polishing pad which is partiallystripped from the elastic base member during polishing, it is necessaryto re-adhere the polishing pad and the elastic base member with anadhesive.

The present invention has been made in consideration of theabove-mentioned situations. Accordingly, it is an object of the presentinvention to provide a polisher such that a polishing pad adhered to anelastic base member is not easily stripped during polishing anddefective polish is not generated.

It is also an object of the present invention to provide a polishingmethod using a polisher such that a polishing pad adhered to an elasticbase member is not easily stripped during polishing and defective polishis not generated.

DISCLOSURE OF INVENTION

As a result of earnest investigations conducted in order to attain theabove object, the present inventor has found out that in theconventional polishing pad with the petal shape, the width of the notchportions is large and the notch portions where the polishing pad isabsent are comparatively lower in stiffness than the portions where thepolishing pad is present, so that the circumferential edge of the lenswill easily get under the notch portions during polishing, resulting inthat the polishing pad is stripped. It has also been found out that thenotch portions are necessary for polishing as water passing grooveshaving the functions of discharging the polishing chips, supplying thepolishing liquid and so on, and when the water passing grooves arereduced in width than in the prior art, concretely, reduced in width to0.1 to 5 mm, it is possible to effectively prevent the circumferentialedge of the lens from getting under the notch portions and to preventthe polishing pad from being stripped.

In order to obtain a polishing pad with the water passing groovesreduced in width, a plurality of pads are used, whereby it is possibleto obtain a polishing pad in which the curved surface of an elastic basemember is covered with the pads while reducing the gaps between the pads(water passing grooves). By making the pads to have a polygonal shape,it is possible to reduce the gaps by setting the sides of the polygonalpads close to each other. It is also possible to reduce the gaps bydisposing pads so as to partially fill the wide notch portions of theconventional polishing pad having the petal shape.

Further, it has been found out that it is preferable to set the regionwhere the polishing pad is provided on the surface of the elastic basemember so as to cover at least the region where the work is brought intorubbing at the time of polishing the work. With such an arrangement,there is no end edge of the polishing pad under which thecircumferential edge of the lens will get, and the effect of preventingthe stripping of the polishing pad is further enhanced.

In addition, by adhering the polishing pad to the elastic base member byuse of a high-tack adhesive having a 180° peel strength according to JISZ 0237 of equal to or more than 1000 g/25 mm, the stripping or the likeof the polishing pad by the circumferential edge of the lens can beeffectively prevented. In this case, the high-tack adhesive may beprovided on the primer layer and the low-tack adhesive layer provided onthe conventional polishing pad.

By making the elastic base member have a curved surface shape, theproperty of following up to the curved surface of the work can beenhanced. Further, by composing the elastic base member of an elasticsheet, it is possible to follow up to the work surfaces having variousshapes by controlling the pressure inside the elastic base member.

As a polishing method, there can be adopted a method in which thepolisher according to the present invention is used and a polishing padprovided on the surface of an elastic base member of the polisher ispressed against the work surface. By composing the elastic base memberof an elastic sheet, it is possible to follow up to the works havingvarious shapes by controlling the inside pressure for pressing theelastic sheet.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows one embodiment of the polisher according to the presentinvention, in which FIG. 1(a) is a sectional view, and FIG. 1(b) is atop plan view;

FIG. 2 is an enlarged sectional view of one embodiment of the polisheraccording to the present invention;

FIG. 3 is a top plan view of another embodiment of the polisheraccording to the present invention;

FIG. 4 is a sectional view showing a method of polishing a concavesurface of a lens by use of one embodiment of the polisher according tothe present invention;

FIG. 5(a) is a general side view showing the condition where a concavesurface of a lens is polished by use of a hard polishing dish, and FIG.5(b) is a top plan view of the polishing dish;

FIG. 6 is a sectional view showing the structure of a commerciallyavailable polishing pad; and

FIG. 7 is a top plan view showing the condition where the commerciallyavailable polishing pad is adhered to an elastic base member.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, a mode for carrying out the polisher and the polishing methodaccording to the present invention will be described below, but thepresent invention is not limited to the following mode.

The work as an object of the polisher and the polishing method accordingto the present invention is not specially limited and may be any onethat has a work surface needing smoothing or mirror surface finishing.The polisher and the polishing method according to the present inventionmay be applied to polishing of a plain surface, a convex surface or aconcave surface, preferably polishing of a concave surface. For example,optical lenses represented by camera lens, telescope lens, microscopelens, focusing lens for stepper, spectacle lens, etc., glass mold forcasting polymerization of a plastic lens, and optical component partssuch as a cover glass of a portable apparatus, etc. may be mentioned asexamples of the work. Hereinafter, description will be made of a plasticspectacle lens as a representative of the work.

The concave surface (on the eyeball side, also called inside surface) ofthe plastic spectacle lens is provided with a spherical surface, arotationally symmetric non-spherical surface, a toric surface, aprogressive surface, or a composed curved surface of these, or the like.On the other hand, the convex surface of the plastic spectacle lens isprovided with a spherical surface, a rotationally symmetricnon-spherical surface, a progressive surface or the like. In most cases,the convex surface is formed by transfer of a mold at the time ofcasting polymerization of a semi-finished lens. The shape of the concavesurface is, in many cases, formed by numerically controlled or the likecutting or grinding of a semi-finished lens. After the shapingprocessing, the shaped surface must be turned to be a desired opticalsurface by mirror surface polishing.

The polisher according to the present invention is applicable tosmoothing or mirror surface finishing of a curved work surface producedby such shaping processing.

FIG. 1 shows the structure of one embodiment of the polisher accordingto the present invention, in which FIG. 1(a) is a sectional view, andFIG. 1(b) is a top plan view. FIG. 2 is an enlarged sectional view ofthe section of FIG. 1(a).

The polisher 1 has a structure in which a polishing pad 3 is adhered tothe outside surface of an elastic base member 2 through a high-tackadhesive layer 4.

As shown in FIG. 1(a), the elastic base member 2 is composed of anelastic sheet, which comprises a dome-shaped portion 21 dome-like inshape, and a ring-shaped flange portion 22 provided integrally with thecircumferential edge of the dome-shaped portion 21 and projectedoutwards. The polishing pad 3 comprises a plurality of regular hexagonalpads 31 the same in size and disposed with their sides close to eachother so as to cover the surface of the elastic base member 2. The gapsbetween the pads 31 are water passing grooves 5 where the pad is absent,and the pads 31 are so adhered that the water passing grooves 5 have apredetermined width W. The water passing grooves 5 function as passagesfor supplying abrasive grains and water and discharging polishing chips.The water passing grooves 5 of the polishing pad 3 are communicated witheach other from the vicinity of the center of the polishing pad 3 to endedges of the polishing pad 3. The formation region of the polishing pad3 on the elastic base member 2 covers the moving region 6 of the workindicated by dots.

The elastic base member used for the polisher 1 according to the presentinvention preferably has a curved surface conforming to the shape of thework. For example, in the case of polishing the concave surface of aspectacle lens, the elastic base member is so shaped as to have thedome-shaped portion 21 shown in FIG. 1(a). As shown in FIG. 1(a), anexample of the dome-shaped portion 21 is an elastic sheet formed in thedome-like shape, which shape is maintained by the inside pressureprovided by use of a pressure fluid. Other examples include an elasticblank material formed into a dome-shaped block, and a dome-shapedelastic sheet of which the hollow portion is filled with other elasticblank material. The thickness of the elastic sheet is preferably 0.1 to10 mm, particularly 0.2 to 5 mm. The elastic sheet preferably has a JISA hardness (type A durometer) of 10 to 100, and a Young's modulus of 10²to 10³ N·cm⁻². Examples of the material of the elastic sheet and theelastic blank material include rubbers such as natural rubber, nitrilerubber, chloroprene rubber, styrene-butadiene rubber (SBR),acrylonitrile-butadiene rubber (NBR), silicone rubber, fluoro-rubber,etc., thermoplastic resins such as polyethylene, nylon, etc., andthermoplastic resin elastomers based on styrene, urethane, etc.

It is desirable that the diameter of the dome-shaped portion 21 of theelastic base member 2 is 1.1 to 10 times, preferably about 1.5 to 5times, the diameter of the lens which is the work to be polished. Bysetting the size of the elastic base member 2 to be greater than thesize of the work to be polished, it is possible to enhance thecircumferential velocity, to enhance the polishing speed and to enhancethe shape follow-up property of the elastic base member 2.

Examples of the polishing pad 3 include fabrics such as felt, non-wovenfabric, etc., sheets composed of a porous blank material made ofpolyurethane or the like, and synthetic resin sheets flocked with shortfibers. In addition, commercially available polishing pads may also beused. A polishing pad 100 for use with a hard polishing dish which iscommercially available has a structure in which a primer layer 104 and,further, a low-tack adhesive layer 105 are laminated on one side of anon-woven fabric 103, as shown in FIG. 6. Though not shown in FIG. 2, inthe case of using a commercially available polishing pad, the primerlayer 104 and/or the low-tack adhesive layer 105 shown in FIG. 6 isintermediately provided between a high-tack adhesive layer 4 and thepolishing pad 3. In this case, a polishing pad composed of the non-wovenfabric 103 provided only with the primer layer 103 or the low-tackadhesive layer 105 may also be used. Incidentally, the primer layer 104is called a binder layer in some cases.

The shape of the polishing pad may be any one that enables the polishingpad to be adhered to the dome-shaped portion 21. On the other hand, thewidth W of the water passing grooves 5 provided in the polishing padadhered onto the elastic base member 2 must be 0.1 to 5 mm, preferably0.2 to 3 mm. The width W of the water passing grooves 5 in such a rangemust be maintained over the entire part of the polishing pad 3. Bysetting the width W of the water passing grooves 5 at such a smallvalue, it is possible to restrain the deformation due to thecomparatively lower stiffness of the elastic base member 2 at portionswhere the pad 31 is absent. As a result, while the function of the waterpassing grooves 5 is maintained, the fear of stripping of the polishingpad 3 by the circumferential edge of the lens is eliminated, andgeneration of defective polish due to stripping of the polishing pad 3can be prevented. Since the water passing grooves 5 function as theabove-mentioned passages, it is desirable that the water passing grooves5 are communicated with each other over the range from the ends to thecentral area of the polishing pad 3.

In order to reduce the width of the water passing grooves 5 of thepolishing pad 3 adhered to a curved surface, it is effective to composethe polishing pad of a plurality of pads and to form the water passinggrooves at the gaps between the pads.

For example, pads polygonal in shape, such as triangular, heptagonal,pentagonal, hexagonal, etc. in shape are used, and one kind or acombination of two or more kinds of the polygonal pads are denselyarranged with their sides close to each other to form the polishing pad,whereby the water passing grooves can be formed with a small width. Thepolygonal pads can be produced, for example, by cutting polygonal padsfrom a pad supplied in a roll form. As shown in FIG. 1(b), a pluralityof regular hexagonal pads 31 the same in size may be arranged with theirsides close to each other so as to cover the surface of the elastic basemember 2, thereby forming the polishing pad 3. In addition, acombination of pentagonal pads and hexagonal pads, as in the case of asoccer ball, is also effective.

In addition, a polishing pad 3 b as used in a polisher 1 b shown in FIG.3 may be mentioned as an example. The polishing pad 3 b is composed of apetal-shaped pad 33 having wide notch portions 32 and elongate pads 34so disposed as to partially fill the notch portions 32, and is adheredto the outside surface of a dome-shaped portion 21. Water passinggrooves 5 are formed as gaps between the notch portions 32 provided inthe petal-shaped pad 33 and the elongate pads 34 disposed in the notchportions 32.

Besides, the pads are not limited to the polygonal pads and the pads forpartially filling the notch portions, and may be pads for partiallyfilling the gaps between the pads. Further, the petal-shaped pads 100 asshown in FIGS. 5 and 7 can be used if the width of the water passinggrooves 101 can be set small.

The region where the polishing pad 3 is provided on the surface of theelastic base member 2 is preferably so set as to cover at least theregion 6 where the work is brought into a rubbing motion at the time ofpolishing the work, as shown in FIGS. 1(b) and 3. For example, thepolishing pad 3 is provided on the elastic base member 2 so that thework surface of the work does not come out of the polishing pad 3 evenwhere the work is brought into an oscillating motion. By this, the riskof the turning-up of the end edge of the polishing pad 3 by thecircumferential edge of the lens is eliminated, and a strippingpreventive effect is further enhanced.

It is desirable that the high-tack adhesive layer 4 used in the polisher1 according to the present invention has, for example, a tack in termsof 180° peel strength according to JIS Z 0237 of equal to or more than1000 g/25 mm, preferably equal to or more than 1200 g/25 mm, mostpreferably equal to or more than 1500 g/25 mm. By use of a high-tackadhesive, the adhesive force between the polishing pad 3 and the elasticbase member 2 is enhanced, and the polishing pad 3 will not easily bestripped.

The adhesive 105 used for the polishing pad 100 for the hard polishingdish 110 according to the prior art is based on the presumption of useby adhering to the hard polishing dish, so that the adhesive force isset to be low taking into account the workability at the time ofstripping and the residue of adhesive, and is of a low-tack type similarto the re-stripping type. The tack of the conventional adhesive in termsof 180° peel strength according to JIS Z 0237 is about 750 to 880 g/25mm.

Incidentally, the general measuring method of 180° peel strengthaccording to JIS Z 0237 is as follows. A half-length portion of a testpiece of 25 mm in width by about 250 mm in length is adhered to acleaned stainless steel plate by use of a roller having a mass of2000±50 g, the test piece is folded back by 180°, and is peeled at arate of 300±30 mm/min to read the force required, under a testtemperature of 23±2° C. and a relative humidity of 65±5%.

The high-tack adhesive 4 is desirably a double-faced adhesive tape,taking into account the adhesive property and workability. Examples ofthe base of the double-faced adhesive tape include non-woven fabric,Japanese paper, polyethylene foam, polypropylene film, polyester film,etc. The kind of the adhesive is not particularly limited, as far as theadhesive has the above-mentioned tack. Examples of the adhesive whichcan be used include rubber-based adhesives such as adhesives based onnatural rubber, SBR, regenerated rubber, or the like, and acrylic-basedadhesives.

Next, a method of polishing the concave surface of a spectacle lens as awork by use of the polisher 1 shown in FIG. 1 will be describedreferring to FIG. 4.

The polisher 1 is fitted to a fitting jig 7, to be used as a polishingtool. The fitting jig 7 holds the polisher 1, forms the inside surfaceside of the polisher 1 as a sealed space, and functions as a passage forintroducing a pressure fluid to the inside of the polisher 1. Further,the fitting jig 7 has the function of fixing the polisher 1 by fittingto a polishing apparatus which is not shown.

The fitting jig 7 comprises a fitting jig main body 71 and a ring-shapedpresser member 72. The fitting jig main body 71 comprises acylinder-shaped tubular portion 711, and a flange-shaped polisherfitting portion 712 provided integrally with an outer circumferentialportion of a top end portion of the tubular portion 711, projected indirections orthogonal to the axis of the tubular portion 711, andcoaxial with the tubular portion 711. The presser member 72 has a flatlower surface and is ring-shaped with an outer circumferencesubstantially the same as the outer circumference of the polisherfitting portion 712. At a lower end portion of the tubular portion 711,a tapered fitting portion 713 for fixing by fitting to the polishingapparatus is projected outwards.

In order to fix the polisher 1 to the fitting jig 7, the flange portion22 of the polisher 1 is mounted on the polisher fitting portion 712, thepresser member 72 is mounted on the flange portion 22 of the polisher 1,and thereafter the presser member 72 and the polisher fitting portion712 are fixed by bolts or the like which are not shown, whereby theflange portion 22 of the polisher 1 is fixed by clamping between thepolisher fitting portion 712 and the presser member 72. As a result, adome-shaped sealed space 23 is formed between the inside surface of thedome-shaped portion 21 and the upper surface of the polisher fittingportion 712, and the sealed space 23 is communicated with the exteriorthrough the hollow portion of the tubular portion 711.

To the convex surface of the work 8 to be polished is joined a workfitting portion 10 fixed by fitting to a chuck of the polishingapparatus through a joining member 9, for example, a low melting pointmetal, a wax or the like. The chuck of the polishing apparatus not shownis driven to rotate, and the work 8 is rotated about its axis at apredetermined rotational speed. In addition, an air pressure, forexample, is exerted on the chuck so that the work 8 can be pressedagainst the polisher 1 at a predetermined polishing pressure. Further,the chuck for supporting the work 8 of the polishing apparatus isbrought into an oscillating motion such that the rotational axis of thework 8 reciprocates between the vicinity of the apex and an end portionside of the dome-shaped portion 21.

At the time of polishing, as shown in FIG. 4, the polisher 1 is fittedto a turntable of the polishing apparatus which is not shown, throughthe fitting jig 7. A fluid such as water, compressed air and the like ata predetermined pressure is fed into the sealed space 23 between theinside surface of the dome-shaped portion 21 and the polisher fittingportion 712, and the inside of the sealed space 23 is maintained at apredetermined pressure, whereby the inside surface of the dome-shapedportion 21 is pressed and tightened by the pressure fluid. In addition,rotation is performed with the center axis of the tubular portion 711 ofthe fitting jig 7 as a rotational axis. Then, polishing is conducted byrotating the elastic polisher 1 about its axis at a predeterminedrotational frequency while swelling the elastic polisher 1 by apredetermined inside pressure, pressing the work 8 against the elasticpolisher 1 by a predetermined polishing pressure while rotating the work8 about its axis at a predetermined rotational frequency, bringing thework 8 into an oscillating motion, and supplying an abrasive-containingslurry 13 from a nozzle 12 to the surface of the elastic polisher 1.

According to such a polishing method, the circumferential edge of thelens 8 can be effectively prevented from getting between the polishingpad 3 and the elastic base member 2, because the polishing pad 3 isadhered to the elastic base member 2 through the high-tack adhesivelayer 4, the width of the water passing grooves 5 provided in thepolishing pad 3 is small, and the polishing pad 3 covers the movingregion 6 of the work 8. Therefore, the polishing pad 3 would not easilybe stripped from the elastic base member 2, generation of defectivepolish due to stripping can be restrained, and polishing can beperformed with high yield.

While an example of polishing the concave surface of a lens has beenshown in the above description, the polisher according to the presentinvention is applicable also to polishing of a flat surface and a convexsurface.

EXAMPLE

Now, the case of polishing and mirror surface finishing a plasticspectacle lens whose convex surface side has been optically finished bya mold and whose concave surface side has been cut to a desired curvedsurface shape, by use of the polisher according to the present inventionwill be described as an example.

First, a desired semi-finished lens is formed through the step ofmolding a plastic spectacle lens, in the same manner as in the priorart. Next, the semi-finished lens thus molded is adhered to the workfitting portion 10 through the joining member 9, and subsequently theconcave surface of the semi-finished lens is cut to a shape conformingto the prescription for the customer by a cutting step. In this example,a semi-finished lens (hereinafter referred to as work 8) shaped to aspherical surface with a radius of curvature of 109.09 mm by cutting wasfitted to the polishing apparatus. The polishing apparatus is fittedwith a polisher 1 having a structure in which a polishing pad composedof a non-woven fabric provided with a primer layer and a low-tackadhesive layer is held on the surface of an elastic base member 2composed of an elastic sheet through a high-tack adhesive layer 4. Thepolishing pad is the polishing pad 3 b shown in FIG. 3, which is presentover the entire area of the region 6 where the work 8 is brought into arubbing motion at the time of polishing.

As the polishing pad 3 b, a non-woven fabric type polishing padavailable under a commercial name of Blue Pad, a product by 3M, wasused. As the high-tack adhesive layer, a double-faced adhesive tapeavailable under the code number #595 (the base is Japanese paper; havingan acrylic-based pressure sensitive adhesive layer, with a tack of 1000g/25 mm), a product by Sekisui Chemical Co., Ltd. was used. As theelastic base member 2, a nitrile rubber member having a hollow shapeobtained by cutting a part of a sphere with a radius of curvature of 80mm and having a thickness of 3 mm and a JIS A hardness (type Adurometer) of 60 was used.

As shown in FIG. 4, the shape of the elastic base member 2 wascontrolled by supplying compressed air at a pressure of 0.6 kgf/cm² tothe inside of the elastic base member 2. A dielectric liquid 13containing an abrasive dispersed therein was supplied from a nozzle 12to the portion between the work 8 and the polisher 1. As the abrasive,Al₂O₃ with a mean particle diameter of 1.2 μm was used.

Under these conditions, polishing was conducted for about 8 min byrotating the work 8 and the elastic polisher 1 at respective speeds of10 rpm and 300 rpm, setting both of them into relative oscillation by amotion mechanism which is not shown, and applying a polishing pressureof 15 kgf by a pressurizing means which is not shown.

Ten works 8 were polished under the same conditions. Polishing wascompleted without the trouble that a circumferential edge portion of thework 8 would get between the polishing pad 3 b and the elastic polisher1, namely, without stripping of the polishing pad 3 b, and a desiredoptical surface could be obtained with each of the ten works 8.

As has been described above, the polisher according to the presentinvention ensures that the polishing pad adhered to the elastic basemember would not easily be stripped during polishing, generation ofdefective polish due to stripping of the polishing pad can be prevented,and polishing can be performed with high yield.

In addition, according to the polishing method of the present invention,the polisher such that the polishing pad adhered to the elastic basemember would not easily be stripped during polishing is used, so thatgeneration of defective polish due to stripping of the polishing pad canbe prevented, and polishing can be performed with high yield.

INDUSTRIAL APPLICABILITY

The polisher according to the present invention is suitable,particularly, for smoothing or mirror surface finishing after cutting ofa concave surface of a spectacle lens or the like.

Besides, the polishing method according to the present invention issuitable for smoothing or mirror surface finishing after cutting of aconcave surface of a spectacle lens or the like, by use of the polisher.

Explanation of Symbols

1, 1 b: polisher; 2: elastic base member; 21: dome-shaped portion; 22:flange portion; 3, 3 b: polishing pad; 31, 33, 34: pad; 4: high-tackadhesive; 5: water passing groove; 6: moving region of work; 7: polisherfitting jig; 8: work (lens); 9: joining member; 10: work fittingportion.

1. A polisher comprising: a polishing pad which is adhered to a surfaceof an elastic base member through a high-tack adhesive layer having a180° peel strength of equal to or more than 1000 g/25 mm, the polishingpad comprising water passing grooves having a width of 0.1 to 5 mm.
 2. Apolisher as set forth in claim 1, wherein said polishing pad is providedwith a plurality of pads, and said water passing grooves are formedbetween said plurality of pads.
 3. A polisher as set forth in claim 2,wherein said pads are polygonal in shape.
 4. A polisher as set forth inclaim 2, wherein said polishing pad is comprised of a pad having notchportions and pads disposed in said notch portions.
 5. A polisher as setforth in claim 1, wherein said polishing pad is provided on said elasticbase member so as to cover at least the region where a work to bepolished is brought into a rubbing motion during polishing of said work.6. A polisher as set forth in claim 1, wherein a primer layer and/or alow-tack adhesive layer is intermediately provided between saidhigh-tack adhesive layer and said polishing pad.
 7. A polisher as setforth in claim 1, wherein said high-tack adhesive layer is adouble-faced adhesive tape.
 8. A polisher as set forth in claim 1,wherein said elastic base member has a curved surface shape.
 9. Apolisher as set forth in claim 1, wherein said elastic base member isprovided with an elastic sheet.
 10. A polisher wherein a polishing padis adhered to a surface of an elastic base member through a high-tackadhesive layer having a 180° peel strength according to JIS Z 0237 ofequal to or more than 1000 g/25 mm.
 11. A polisher as set forth in claim10, wherein said polishing pad is adhered so as to cover at least theregion where a work to be polished is brought into a rubbing motionduring polishing of said work.
 12. A polisher as set forth in claim 10,wherein said elastic base member is comprised of an elastic sheet havinga curved surface shape.
 13. A polishing method comprising: polishing awork to be polished by pressing a polishing pad of a polisher against awork surface of said work, said polisher having said polishing padadhered to a surface of an elastic base member through a high-tackadhesive layer having a 180° peel strength of equal to or more than 1000g/25 mm, and said polishing pad comprising water passing grooves havinga width of 0.1 to 5 mm.
 14. A polishing method as set forth in claim 13,wherein polishing is conducted while pressing an inside surface of saidelastic base member which is comprised of an elastic sheet anddome-shaped by a pressure fluid.
 15. A polishing method as set forth inclaim 13, wherein said work is oscillated while said polisher and saidwork are rotated respectively about their axes.
 16. A polishing methodas set forth in claim 13, wherein said polishing pad is provided with aplurality of pads, and said water passing grooves are formed betweensaid plurality of pads.
 17. A polishing method as set forth in claim 16,wherein said pads are polygonal in shape.
 18. A polishing method as setforth in claim 16, wherein said polishing pad is provided with a padhaving notch portions and pads disposed in said notch portions.
 19. Apolishing method as set forth in claim 13, wherein said polishing pad isprovided on said elastic base member so as to cover at least the regionwhere said work is brought into a rubbing motion during polishing ofsaid work.